The proposed research will explore the possibility of mapping, in a simple and accurate fashion, the ultrasound attenuation properties of an unknown biological medium. The ultrasound attenuation has been found to be one of the most relevant parameters for ultrasound diagnosis and tissue characterization, and determination of the acoustic attenuation often allows differentiation between normal and pathological tissues, and between different types of tumors or cancer lesions. Because the proposed attenuation technique requires measurements at two different frequencies, a transducer material with very broadband characteristics is needed. This requirement can be fulfilled by making use of piezoelectric polymer transducers, the socalled PVDF transducers. PVDF material has been used mainly for hydrophones, but due to improved electro- acoustic conversion, it is now gaining wider use, although mainly for industrial applications. A limiting factor is still the rather high electrical impedance of the PVDF transducers. The attenuation is determined from pulse-echo measurements, using short bursts, say, 4 - 6 cycles long, at two different frequencies. Clear spectral separation of the bursts at the two different frequencies is needed. It can be shown that the log of the ratio of the received signal amplitudes at the two different frequencies, when differentiated and normalized, will yield an absolute measurement of the attenuation. The technique may eventually lead to a broader clinical use of the attenuation as a diagnostic factor. The first aim of the proposed research is to demonstrate the applicability of the method by making measurements with PVDF transducers on media with known attenuation. Additional aims are to investigate effects of a number of practical factors that may need to be considered. These factors include trade-off's between burst length and resolution; compensation for change in transducer aperture at the two different measurement frequencies; excluding regions with insufficient signal-to-noise ratio, alignment of the demodulated waveforms, before the ratio is calculated, and sensitivity correction.